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Enhanced Reliability of Radiation-hardened III-V Semiconductor-based Field Effect Transistors Using C-doped Low-temperature Buffer

Award Information
Agency: Department of Defense
Branch: National Geospatial-Intelligence Agency
Contract: N/A
Agency Tracking Number: 41266
Amount: $97,153.00
Phase: Phase I
Program: SBIR
Solicitation Topic Code: N/A
Solicitation Number: N/A
Solicitation Year: N/A
Award Year: 1998
Award Start Date (Proposal Award Date): N/A
Award End Date (Contract End Date): N/A
Small Business Information
119 Technology Drive
Bethlehem, PA 18015
United States
HUBZone Owned: No
Woman Owned: No
Socially and Economically Disadvantaged: No
Principal Investigator
 Scott Massie
 (610) 861-6930
Business Contact
Phone: () -
Research Institution

Low-temperature MBE grown GaAs (LT-GaAs) contains a high concentration of excess As which gives rise to ultra-fast carrier-trapping time and excellent radiation hardness. In as-grown layers most of this excess As is in the form of As(Ga) antisite defects, of which only ~1% are ionized. Thermal annealing upon overgrowth with a device structure or during device processing results in a decrease of the As(Ga) concentration by about a factor of 100, accompanied by out-diffusion of excess As into adjacent layers. The benefits of LT-GaAs buffer layers for device isolation and increased radiation hardness can thus be realized only if their stability can be improved. Doping the LT-GaAs layers with Be (LT-GaAs:Be) can thermally-stabilize As(Ga) antisite defects and increases their incorporation. However, Be is known to be a relatively mobile element at high temperatures and LT-GaAs:Be may suffer from undesirable concentration-dependent diffusion at high doping levels. Here, we propose the use of C as an alternative p-type dopant in LT-GaAs. The combination of larger lattice concentration and superior thermal stability should make LT:GaAs:C a promising technology for radiation-hard field effect transistor (FET) applications. The proposed technology will offer enhancement in radiation hardness, thermal stability and reliability of III-V semiconductor-based field effect transistors compared to conventional undoped and Be-doped low-temperature buffers.

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